But the state said paying for construction has never been part of the deal.

More than $150 million has been spent at the site of the failed Wayne County Jail project, county commissioners say, and it would take a significant investment to add needed beds to the state-owned facility on Mound, build a courthouse and move operations from downtown to northeast Detroit. It’s unclear how much the total cost of the move could be.

“It’s taking us into further debt, as far as I’m concerned,” said Commissioner Ilona Varga, D-Lincoln Park.

Wayne County Executive Robert Ficano’s administration has been pushing for a move to the Mound Road facility since late spring after AECOM — the project manager on a $300-million, state-of-the-art jail being built off Gratiot at St. Antoine — reported that costs had soared nearly $100 million over budget. The county has halted construction on the jail while it investigates what went wrong.

Rock Ventures would pay $50 million for 15.5 acres that includes the jail site, the Frank Murphy Hall of Justice, Wayne County Jail Division 1 and 2 on Clinton Street and the Wayne County Juvenile Detention Facility at St. Antoine and Macomb.

Part of the money — about $30 million — would come after the county vacates the court, jails and juvenile detention facility. The acres are in the shadows of Greektown Casino, which Gilbert owns. Rock Ventures plans to build retail, residential and commercial spaces on the land.

An official with Rock Ventures could not be reached for comment.

Rock Ventures would take the parcel as is and assume responsibility for demolition of the partially built jail and other facilities. It also would work with the county as a developer to assist with completion of the jail at the Mound Correctional Facility, which would require renovation.

The commission is expected to meet next week to discuss a 90-day option agreement between the county and Rock Ventures, which would allow time to explore whether the move is a financially responsible one for both sides. Some county commissioners have kept open the option of rejecting any private development plan and resuming construction at the current site.

Commissioner Kevin McNamara, D-Belleville, said Tuesday he recalled state officials telling the commission they would build the courthouse. Mario Morrow, a state spokesman, said no financial assistance has been offered.

“We’re advising,” Morrow said of the state’s role in the county’s move to the Mound facility, “but we haven’t said anything about money or anything like that.”

That puts the county back on the hook for a new courthouse that could cost as much as $300 million, according to a lawsuit settlement between the county and the 3rd Circuit Court, which began in 2008 amid claims that the county had underfunded the courts.

“We approved $220 (million) for a jail that was attached to a court facility, and that is what we need at Mound Road — at a minimum,” said McNamara, also chair of a special task force looking at what went wrong with the jail project. “If we have to build out a court option, (the move) is a nonstarter.”

The county went to voters for the $300 million in bonds for the project.

About $155 million has been spent, county officials said recently, but that continues to rise because of ongoing closeout details at the site. That leaves $145 million from the initial offering, along with the $50 million Rock Ventures would pay.

The county also has filed a lawsuit against AECOM, saying the firm was responsible for more than $40 million in cost overruns during construction.

Andre Hindo, a project manager with Detroit construction firm Walsh Construction, which bid for the now-stalled Wayne County Jail project, said a buildup at the Mound Correctional Facility and the construction of a courthouse at the site could not happen for the money the county has left over.

“I don’t think so,” said Hindo, who added that relocating to the Mound facility would be an “ideal condition” without enough funds to build the proposed jail.

Commissioner Ray Basham, D-Taylor, said since many are housed at the county jail on charges mandated by the state, the state should be quicker to assist the county with its relocation.

“The state has some interest in righting this ship, weighing in a little heavier,” Basham said. “They’re saying: ‘We’ll give you all our facility for $1.’ That’s not good enough. Last I knew, Wayne County was a part of the state.”